Gaseous discharge tube with arc discharge



July 10, 1951 E. w. HULLEGARD I 2,559,769

GASEOUS DISCHARGE TUBE WITH ARC DISCHARGE Filed June 3, 1949 2 Sheets-Sheet l July 10, 1951 E. w. HULLEGARD 2,559,769

CAsEoUs DISCHARGE TUBE WITH ARC DISCHARGE Filed June 3, 1949 2 Sheets-Sheet 2 1:2111 612760Z@ again@ Patented July 10, 1951 GASEOUS DISCHARGE TUBE WITH ARC DISCHARGE Erik Waldemar Hullegrd, Stockholm, Sweden, assigner to Telcfonaktiebolaget L M Ericsson, Stockholm, Sweden, a company of Sweden Application June 3, 1949, Serial No. 96,889 In Sweden June 10, 1948 7 Claims. 1

The present invention relates to a gaseous discharge tube of the same kind as is described in patent application No. 784,485, in which a discharge between two electrodes, an anode and a cathode, may be given a thread shaped path through the gas in the tube. Such a discharge may be produced by a suitable dimensioning of the electrodes and suitable choice of the gas pressure in the tube and the Voltage between the electrodes. Outside the discharge path only an unimportant ionization of the gas is obtained.

The path in space of such an arc discharge can be inuenced by means of a magnetic field, the lines of force of which form an angle with the plane containing the arc. An element of length oi the arc will thereby be actuated by a force, which is dependent on the direction of the magnetic iield, the induction, the strength of the current in the arc and the length of the arc element.

The gaseous discharge tube according to the invention contains besides the cathode and the anode an arbitrary number of further electrodes,

` below called contact electrodes, which are arranged in different directions out from an axis through the centre of the cathode and the anode.

In such a device the said qualities of the arc are utilized to cause the arc to move round the axis in such a way that it will be brought into contact with the contact electrodes and thus actuate the circuits connected to them. The tube may hereby be used for many diterent purposes, for example, as a connecting device in cyclically working switches, for nders and for numerically working selectors and so on.

In a cyclically working switch a rotating movement of the arc is produced by means of the magnetic eld, during which movement the arc by turns touches the contact electrodes arranged to lie on that surface which is described by the arc. Circuits may thereby be produced either between such an electrode and the cathode respectively the Yanode via the arc or between different electrodes, which are actuated simultaneously by the arc. It may then be suitable to arrange two or more such electrodes close to each other, S that they form an especial contact device, within which a considerably much greater current may arise in the contact moment, if the voltages in the circuits to be influenced by the or so, that it may remain also after this moment.

A rotating movement of the arc may in different ways be produced by means of the magnetic field. One manner is to use a rotating magnetic field. which during the rotation always forms an angle with the arc. In this case the anode as well as the cathode may be point shaped and the arc will describe a spool shaped surface at the rotation with the magnetic field rotating suitably in a plane perpendicular to a line through the anode and the cathode.

One of the electrodes, preferably the anode, may also be constructed with a circular or ringshaped surface, the edge of which suitably almost everywhere has the same distance to the other electrode. rlhe arc will then when rotating described a surface, which on the whole is shaped conically.

With a ring shaped construction of the anode or that part of the same as is lying nearest to the cathode, the rotating magnetic eld may further be replaced by a stationary eld forming an angle with the arc in all different positions of the same.

Especially suitable elds for this purpose are partly radial elds directed outwards from an axis through the centre of the ring and the cathode and partly axial fields acting perpendicularly to the plane of the ring. that is in the same direction as said axis. In the latter case the cathode may preferably be arranged centrally in or near the plane of the anode and the arc will then when rotating touch a circular surface and a cone respectively, the top angle of which is near 180.

The rate of the rotation of the arc at stationary magnetic elds will be proportional to the field strength, and thus the connection time and the interval between these may be regulated by regulating the strength of the magnetic field.

If the tube is to be used as a numerical selector with a certain initial position for the arc it may be constructed unsymmetrically or arranged in an unsymmetrical magnetic eld, so that the arc is held in balance at a desired contact electrode by means ofdthose forces, which actuate the arc and which are altered because the length of the arc is altered, due to the asymmetry of the movement from the initial position. If the tube for instance is constructed with a ring shaped anode. this may be arranged in such a Way that its plane will form an angle deviating from with ad axis through the centres of the anode and the cathode, so that a desired alteration of the length of the arc when moving is obtained. A certain desired baiame may be obtained both by changing the magnetic leld and by changing the current of the arc. This may also be caused to pass the desired path through the tube by means of suitably arranged screens and also due to them to be restrained from passing the point of the anode lying farthest away from the cathode.

At maintained symmetry in the tube itself the directing force of the arc may be obtained from a magnetic field, the strength of which increases with the distance from the initial position of the arc.

The anode of the tube may however also be constructed in another way than ring-shaped, for

instance cylindrical, and be so arranged in rela.

tion to magnetic field and cathode, that the arc will be lengthened, when turned by the magnetic field. so that a counter-directed force is obtained which holds the arc in balance in front of the desired contact electrode.

Some different embodiments of tubes according to the invention are shown in the annexed figures, of which Fig. 1 indicates an embodiment of a. tube having a small cylindrical anode and a cylindrical cathode surface arranged centrally in the tube, Fig. 2 a schematic section through a tube having an anode performed as a ring and a cylindrical cathode surface, Fig. 3 the same tube seen perpendicularly to the axis of the tube, Fig. 4 a section through a tube with a ring shaped anode and parts arranged flxedly in the tube for generating a magnetic field directly radially from the axis of the tube, Fig. 5 a section through a similar tube with the parts generating the magnetic field lying within reach outside the envelope of the tube, Fig. 6 a section through a tube with a ring shaped anode, in which there is a cathode surface arranged centrally in relation to the ring shaped anode near the centre and further a device for generating a magnetic field perpendicular to the plane of the anode. In Fig. '7 the same tube is seen from above. Fig. 8 is a sectional view through a tube having a cathode surface arranged eccentrically in relationship to the anode and in Fig. 9 this is a top plan view of the same tube.

Fig. 1 shows a. glass envelope I containing gas. for instance rare gas, at a pressure chosen in such a way that an arc discharge may be produced therein. In one end of the glass envelope a glass foot 2 carrying a cathode system is ar- Y ranged and in the other end a glass foot 3 carrying the anode and a number of contact electrodes. The cathode I is indirectly heated and provided with an electron emitting layer at the one end surface. The junction lines to the cathode and Ithe heat wires are connected to a base I0. The

anode 5 is arranged centrally in the tube at the other glass foot and between the anode and the cathode a number of contact electrodes 6 are arranged radially at the same distance from a junction line between the anode and the cathode. The contact electrodes 6 are mounted on an insulating ring 1, which is held by a llpport 8. Leads 9 from the contact electrodes are drawn out through the glass foot. The tube is surrounded by devices generating a turning or rotating magnetic field, of which a pair of coils I I, I I is shown in the figure.

Between the anode and the cathode the thread shaped arc discharge I3 may be produced, which by means of the revolving magnetic eld may be bent out towards the contact electrodes and caused to touch the same when the magnetic 4 field is moving. Thereby the contact electrode 6. which is actuated by the arc, will get into conductive connection with the anode and the cathode, and therefore a circuit containing the contact electrode and one of the last mentioned electrodes, can be influenced.

In Fig. 2 there is shown schematically a section through a device, which differs from the preceding one partly thereby that the anode I4 is constructed in the shape of a ring and partly thereby that the tube is provided with groups of contact electrodes containing each two electrodes I5 and I6. Fig. 3 shows the same device seen from above. The contact point of the arc at the anode will on alteration of the direction of the resultant of the magnetic elds'produced by the coil systems II, II and I2, I2 move on the ring. In the position of the discharge arc I3 shown in the figures the resultant of the magnetic field has that direction which is indicated by the arrow I1. When the arc touches a pair of electrodes I5, I6 the electrodes will be connected with each other, wherebyya circuit, in which'they are contained, may be influenced. By using two electrodes, which are contacted simultaneously by the arc, it is possible, if desired, to separate the circuits connected to the respective pairs of electrodes, be-

sides which, if the distance between the electrodes is made short, the contact resistance may be made very low. The groups of electrodes may of course be contacted with more than two electrodes in the same group and it is also possible to arrange different groups in such 'a'wayfthat they are actuated simultaneously by the arc.

In Fig. 4 such a tube is indicated, which is provided with two groups of electrodes comprising each two electrodes I5 and I6, and I8 and I9. respectively, which are contacted simultaneously by the arc and which may be contained in different circuits or in different places in the same circuit.. The tube shown in this figure is be-1 sides constructed with a cup shaped magnet system performed in such a way that a radial magnetic field is obtained, the centre axis oi which coincides with the axis of the tube. Centrally in the cup 20 of ferro-magnetic material there is a core 2I anda radially magnetized permanent magnet 22 generating a magnetic held between the core and the walls of thecup, where the ring shaped anode I4 is mounted. In such a magnetic field the discharge -arc will rotate, generating a conical surface, with an angular velocity that is determined by the current of the arc and the magnetic induction in the air gap. At the field direction indicated by the arrows 23 the arc is rotating in clockwise direction, seen from above.

The field may of course also be generated by means of a coil, whereby one may rather choose the embodiment shown in Fig. 5 having a magnetic system arranged outside the envelope of the tube. The central core of the magnet system is inserted in a recess of the glass envelope I. round which the ring shaped anode is arranged. The magnetic field indicated by the arrows is obtained by letting a current pass through the magnet winding 24. The rate of rotation of the arc may be regulated with the magnetizing curr` 1tas well as with the current of the arc.

In Figures 6 and '7 a. tube is shown, where the cathode 4 has been arranged centrally in the tube near the centre of the ring shaped anode I4. said centre containing single contact electrodes 6. A magnetic field crossing the plane of the anode at rightangles is generated by means of cally mounted with respect to the center of the the value corresponding to the deflection of the arc to the point of the anode lying farthest away from the cathode, the arc begins to rotate with a velocity, which is lowest at this place and highest at the place of the anode lying nearest to the cathode.

The invention is of course not limited to the 'embodiments shown above; many others may be invention.

I claim:

1. A gaseous discharge tube having an envelope, an anode and a cathode therein in alignment and spaced apart, a plurality of contact electrodes arranged between said anode and cathode and on lines normal to the line between the anode and cathode, means for producing a string shaped discharge arc between said anode and cathode and across one of said contact electrodes, and magnetic means for rotating said discharge arc to make it successively contact the other contact electrodes.

2. A gaseous discharge tube having an envelope, an anode in the form of a closed curve in said envelope, a cathode spaced on a line normal to the plane of said curve and through the center of same, a plurality of electrodes arranged between said anode and cathode and in lines normal to the line between the cathode and the plane of the anode, means for p roducing a string shaped discharge arc between the anode and cathode thought of, which fall within the scope of the .and across one of said contact electrodes, and

string shaped arc between said anode and cathode `and across one of said contact electrodes, and

magnetic means for rotating said discharge arc to make it successively contact the other contact electrodes. i

6 4. Av gaseous discharge tube having an envelope, an anode in the form of a circle in said envelope, a cathode closely spaced with respect to said anode and positioned on a line normal to the plane of said circle and through the center of same, a plurality of electrodes arranged be# tween said anode and cathode and on lines normal to the line between the cathode and the plane of the circle vof the anode, means for producing a string shaped arc between said anode and cathode and across one of said contact electrodes, and magnetic means for rotating said discharge arc to make it successively contact the other contact electrodes.

5. A gaseous discharge tube having an envelope, an anode and a cathode therein in alignment and spaced apart, a pluralityl of pairs of contact electrodes arranged between said anode and cathode and on lines normal to the line between theanode and cathode, means for producing a string shaped discharge arc between said anode and cathode and across at least one pair of said contact electrodes, and magnetic means for rotating said discharge arc to make it successively contact the other pair of contact electrodes.

6. A gaseous discharge tube having an envelope, an anode and a cathode therein in alignment and spaced apart, a plurality of pairs of contact electrodes arranged between said anode and cathode and with the electrodes of each pair spaced apart a relatively short distance with respect to the distance between`the anode and cathode and positioned on lines normal to the line between the anode and cathode, means for producing a'string shaped discharge arc between said anode and cathode and across at least one pair of said contact electrodes, and magnetic means for rotating said discharge arc to make it successively contact the other pairs of contact electrodes.`

'1. A gaseous discharge tube having an envelope, an anode and a cathode therein and spaced apart, at least two groups of spaced pairs of contact electrodes arranged between said anode and cathode and with the electrodes of each pair spaced apart in relatively short distance with respect to the distance between the anode andthe cathode and positioned on lines normal to the line between the anode and cathode, means for producing a string shaped discharge arc between said anodeand cathode and across at least one pair of each of said contact electrodes, and magnetic means for rotatingsaid discharge arc to make it successively contact simultaneously other pairs in the groups of contact electrodes.

ERIK WALDEMAR HULLEGARD.

.1 REFERENCES CITED The following references are of record the nle of this patent: i

UNITED STATES PATENTS Number 4311701 y Germany June 24,1920 

